The angle of depresion of the top and bottom of 50 m high building from the top of a tower ere 45°
and 60° respectively, Find the height of the tower and the horizontal distance between the tower and the
building (Use √3 - 1.73)
Answers
Solution: tan ∅ = Perpendicular/Base
→ tan 45° = AE/ED
→ 1 = AE/ED
→ AE = ED
→ tan 60° = AB/BC
→ √3 = (AE + BE)/BC
Now, AE = DE and BE = DC (opposite sides of rect. BCDE)
→ √3 = (DE + DC)/BC
Now DE = BC (opposite sides of rect. BCDE)
→ √3 = (BC + DC)/BC
→ √3 = 1 + DC/BC
→ √3 = 1 + 50/BC
→ (√3 - 1) = 50/BC
→ BC = 50(√3 + 1)/(√3² - 1²)
→ BC = 25(√3 + 1)
→ BC = 68.25 m
Now, BC = ED = AE
→ AE = 68.25 m
→ AB = AE + BE
→ AB = 68.25 m + 50 m
→ AB = 118.25 m
Answer: Height of tower is 118.25 m and horizontal distance between building and towet is 68.25 m.
________________________________________________
Tan = 54° AE / ED
= AE / ED1
= AE / EDAE = ED
________________________________________________
Tan = 60° = AB / BC
= √3 = ( AE + BE ) / BCAE = DE , DE
= DE ( BCDE )
= √3 = ( DE + DC / DC )
= BE = BC ( BCDE )
________________________________________________
= √3 = ( 3 C + DC ) / BC
= √3 = 1 + DC / BC
= √3 = 1 + 50 / BC
= √3 - 1 = 50 / BC
= BC = 50 ( √3 + 1 ) / √3² - 1²
= BC = 25 ( √3 + 1 )
= BC = 68.25 m
= BC = ED = DE
= AE = 68.25 m
= AB = AE + BE
________________________________________________
= AB = 68.25 m + 50 m
= AB = 118.25 m